Multicathode glow discharge device



1952 M. A. TOWNSEND MULTICATHODE GLOW DISCHARGE DEVICE Filed Dec. 22,1950 FIG. 3

IN VE/V 70/? A. TOWNSEND A T TORNEV Patented Aug. 12, 1952 MULTICATHODEGLOW DISCHARGE DEVICE Mark Townsend, Berkeley: Heights, N. J assignor toBell Telephone'Lahoratories, Incorporated, New York, N. Y., acorporationof New York . Application December 22, 1950, serial No. 202,284

,disclosed in. the application Serial No. 101,322

filed-June 25, 1949 of M. A. Townsend, now Patent 2,575,370, grantedNovember 20, 1951.

Devices of the type disclosed in the above-identified applicationcomprise, in general, two groups of cathodes mounted in alternaterelation and in cooperative relation with a common anode. The severalcathodes are constructed and arranged to provide what has been termed apreference mechanism whereby in response to directcurrent signal pulsesapplied between the two groups of cathodes the discharge is stepped orshifted in one direction from one cathode-anode gap to the next adjacentone, the number of steps being in accordance with the number of pulsesapplied.

One general object of this invention is to improve gaseous dischargedevices of the type above described. More specific objects of thisinvention are to enable stepping of the discharge from cathode tocathode in such devices, directly in accordance with alternating-currentsignals, and to simplify the structure of multicathode, glow discharge,stepping and counting devices. I In one illustrative embodiment of thisinvention, a discharge device comprises anarray of electrodes eachcapable of .acting'as a glow. cathode. Each electrode is ,constructed'tohavetwo portions ofdifierent efficiencies as glow discharge sustainingelements and the several electrodes are mounted with the portion ofhigher efficiency of each in juxtaposition to the lower efficiencyportion of a next adjacent electrode. An output circuit may be connectedto one or more of the electrodes or a plurality of output circuits maybe connected individually to severalrespe'ctive electrodes;

In accordance with one feature of this invention, the electrodes in thearray are'electrically grouped and energized in accordance withalterhating-current signals so that each electrode acts alternately'as acathode and an anode, whereby in response to such signals a discharge,sustaining between any two adjacent electrodes, is stepped along thearray, advancing two gaps for each cycle of the applied signals;

More specifically, in accordance with one feature of this invention,alternate electrodes are connected electrically in two groups and thealternating-current input signals, of amplitude sufficient to sustain adischarge between adjacent electrodes; rem in d be are 'PW een Claims.(Cl. 313-188) The invention'and the above-noted and other featuresthereof will be understood more clearly and fully fromthe followingdetailed description with reference to the accompanying drawing inwhich:

Fig. 1' is in part a diagram and in part a circuit schematicillustrating the principal elements and the organization thereof in agaseous discharge device constructed in accordance with this invention;

Fig. 2 is a diagram showing a multistage discharge device illustrativeof one embodiment of this invention, wherein a plurality of outputcircuits individual to alternate electrodes are provided; and

Fig. 3 is a perspective viewshowing details of construction of adischarge device illiis'trative'of this invention.

, Referring now to the drawing, the discharge deviceillustr-ated inFigs. 1 and ,2 comprises an enclosing vessel It having therein anionizable atmosphere, such as a rare gas or a mixture of rare gases.'Mounted within the vessel is'a group of electrodes HA, H3 and HC each ofwhich has a hollow or channel-shaped portion 2, a tail portion [3 andastem or support portion, 1 4. The several cathodes constituting thisgroup are con- 'nected together electrically by aftie wire 'I 5. Also"mounted within the vessel and in alignment and in alternate relationwith the electrodes l I are a plurality of electrodes .lG'A, NE and [60.Each of the electrodes l6, likev the electrodes ll, includes a hollow orchannel-shaped portion, a tail portion and a stem or support portion.The electrodes 16 "are connected together electrically by a tie wirel'l.

The electrodes H and'lG advantageously are formed'of sheet refractorymetal, suchas molybdenum or tantalum. As shown clearly in Fig. 1, eachof the electrodes It is mounted with its hollow' or channel-shapedportion in juxtaposition to the tail portion tothe next succeeding.electrode I l. and with its own tail in juxtaposition to the hollow orchannel-shaped portion of the next preceding electrode ll. When adischarge sustains at any of the electrodes, the discharge willconcentrate and highest ionization will obtain at the channel-shapedportion of that electrode the respective resistor.

sustaining at electrode HB and the electrodes I6 are pulsed positiverelative to the electrodes H the tail portion of the electrode 16B willbe adjacent a region of high ionization density whereas the electrode[6A will be adjacent a region of low ionization density. Consequently,the discharge will beshifted'from electrode 1 M3 to electrode ISB ratherthan in the opposite direction. Thus, by virtue of the preferencemechanism noted, stepping or shifting of the discharge occurs to theright in Fig. 1.

Adjacent the electrode I [A is an auxiliary electrode [8 which may beconnected to a pulse source not shown by way of resistor 22. Theelectrodes l6 are connected to a source of alternating-current inputsignals through series connected resistors l9 and 28 having associatedtherewith a condenser 21 as shown.

In the operation of the device, a positive starter pulse, indicated atP1, is .applied to the auxiliary electrode l8'whereby a discharge isinitiated between the electrodes HA and I8, the electrode HA acting asacathode. On the first positive 'half cycle of the input signal,indicated at P2, a discharge is established between electrodes HA and16A with the electrode l IA acting as a cathode and the electrode 16Aasan anode. On the succeeding negative half cycl of the inputsignal thepolarity of the electrode relative to the electrodes II is reversed andbreakdown occurs to the electrode ISA acting as a cathode. At firstbecause of residual ionization from the first positive half cycle of theinput signal, electrode HA will act as an anode. However, because of theconstruction of the electrode I 6A as above described, ionization willbe high or intense in the region between the electrodes 16A and HB andthe discharge obtains between electrode |6A acting'as a cathode andelectrode HB acting as an anode. .On the next succeeding positive halfcycle of the input signal, electrode IEA becomes an anode and'electrodeHB acts as a cathode. On the next succeeding negative half cycle ofthemput signal electrode 1 IB becomes the cathode and electrode 16Bfunctions as an anode.

Thus for each half cycle of the input signal the discharge is moved oneposition along the row of "electrodes advancing in effect from onecathode to the next succeeding one.

Although in the construction illustrated in Fig. '2 six dischargesustaining electrodes are shown, it will be understood, or" course, thata greater number may be employed. For example, as shown in Fig- 1, thedevice may comprise twenty such electrodes and be capable of countingten complete. or twenty half cycles. Each of the electrodes l I may haveassociated therewith a suitable output'or indicating circuit indicatedgenerally by resistors 23 whereby when a discharge sustains at any ofthese electrodes a pulse is produced across These pulses may berecorded; for example in' the manner described in the 3 application ofM. A. Townsend heretofore identified.

ltwi'llibe-understood, of course, that theinput signal "should be ofamplitude sufiicient to sustain --spective tie rings l5 and I1.

4 nal. Specifically, the parameters of these impedances are correlatedso that with a neon filled tube a delay of the order of 50 to 200microseconds occurs in the process of reversing the voltage across thetube. The delay must of course be less than the deionization time of thegas involved.

One physical embodiment ofa discharge device constructed in accordancewith this invention is illustrated in Fig. 3. As there shown, theseveral electrodes H and 16 in alternate relation 'aremounted'in acircle, the electrodes 1 I and electrodes 16 being interconnectedelectrically by re- These tie rings in turnare connected to leading-inconductors 24, in turn connected to terminal prongs 25 upon a base 26 towhich the enclosing vessel H1 is afiixed. .It will beunderstood, ofcourse, that if in the device illustrated in Fig. 3 individual outputsfor the several electrodes l8 are desired, respective leading-inconductors for these lectrodes will be provided as in themannerindicated in Fig. 2.

Itwil-l be appreciated that inasmuch as in the device illustrated inFig. 3 the several electrodes l i and I6 are mounted in circular array,frequency dividing maybe btained one output pulse being realized atone-electrode for each ten complete cycles of an alternating-currentinput signal.

Although specific embodiments of this invention have been shown anddescribed, it will be understood that they are but illustrative and thatvarious modifications may be made therein without departing from thescope and spirit of this in- 'vention.

What is claimed is:

l. A gaseous discharge device comprising an array of similar electrodeseach capable of functioning as a glow cathode, means electricallyconnecting said electrodes in two groupswith the electrodes of the twogroups in alternate relation, said electrodes including'means'defining adirectional preference mechanism, and means for impressing between saidtwo groups alternatingother alternate electrodes alternately positiveand negative relative to said one group sufficientlyto sustain adischarge between adjacent electrodes.

3. A gaseous dischargedevice in accordance with .claim.2 comprising loadcircuits individual to the electrodes in said one group.

4. A gaseous discharge device comprising a plurality of refractory metalelectrodes each having a channel portion and a tail portion, saidelectrodes being mounted in a row with the channel portion of eachadjacent the tail portion of the next succeeding electrode, meanselectrically connecting said electrodes in two groups with theelectrodes of the; two groups in alternate relation, and means forimpressing between said two groups alternating-current signals ofamplitude sufiicient tosustain a glow dischargebetween any two adjacentelectrodes.

'5.A gaseous discharge device comprising a plurality ofrefractommetalelectrodes each having trode, and means for stepping the discharge along10 Number said row comprising means for applying alternating-currentsignals between said two groups.

MARK A. TOWNSEND.

5 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date 2,524,213 Wales Oct. 3, 1950

